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Increasing Your SEO Success By Optimizing Your Images
By: Stephen Pitts

Yes, yet another test, and I will return to the rest of the link development series soon, but I have been sitting on this test for some time and I thought you deserve to see the results. The last test on the value of image optimization was limited to Google and Yahoo only and utilized the title and alt attributes in image links.

This is a bit different and only utilizes these elements when the image isn't a link and it uses four different images with these elements so we have multiple sources to test on the same page. This will give us the opportunity to see if one of these elements might have no weight whatsoever.

So, let's get to it.

Here are the details of the of the test:

1. Four pages have been built with the same four images.
2. Each page was given a non-descriptive name, unrelated to the any of the four targeted keywords or any topical relevance and a topically relevant H2.
* Alpha
* Beta
* Charlie
* Delta
3. Each of these pages have the same parent page, this was given a topical name, related to each of the targeted keywords by topical relevance only.
* Hotels - H-Parent
4. Each of these pages contain four images and they have been named for their respective keyword along with a H3 tag with the same keyword.
5. Each of the images contain the following elements:
* Alpha - no alt, no title
* Beta - alt, no title
* Charlie - no alt, title
* Delta - alt, title
6. The parent of these pages will be located on a rarely visited page (my html sitemap) by users and crawled regularly by search engine spiders.
7. These page will target the following keywords:
* Ramada
* Radisson
* Marriott
* Hilton
8. Each of these pages were set to publish at the same time in the future, schedule for: Feb 23, 2009 @ 00:01, to ensure each page was available at the same time.
9. When cached by all major engines, we will conduct a site search for the priority of pages in the SERPs across all engines for each of the targeted keywords. This will measure the impact of alt and title elements by seeing which of the pages ranks higher with no external impacts.

My initial assumption was that the title element has little, if not no value, however, based upon the results of this study, it appears that this is not the case.
Digesting the Results

First, one of the first things to recognize is that results were consistent for each keyword in each engine. This let's us be sure (at least within this test) that each engine values each element and combination differently. Each use of alt and title element have a value (even if it is minimal).
Google

Ranking in order:
- Alt Only
- None
- Title Only
- Both

The alt element definitely has the most weight, but it looks like the title element might have a negative affect on ranking and it appears (to me) that use of both may get an over optimization penalty. Interestingly, Google ranked the use of both elements in the last test (which were image links) as it's first result and alt only as second, so, it is reasonable to say that if you are trying to rank better in Google, then using the alt element for your images will be the best behavior.
Yahoo

Ranking in order:
- None
- Alt
- Both
- Title Only

The most interesting of all of the search engine's results, Yahoo ranks the use of alt and title elements below the no use at all, but the title element ranked lowest. So, it is reasonable to say that the alt element has the most weight and the title element might have a negative impact on rankings. Even better, Yahoo ranked differently in the previous test, as did Google, using the title only ranked first before and fourth in this test; however, using the alt element ranked second for both tests. If you are trying to rank better in Yahoo, then using the alt element will have the best affect, ranking second in both tests.
Bing

Ranking in order:
- Alt
- None
- Both
- Title Only

Again, the alt element shows to have the most weight, and, once again, it appears that the use of the title element may have a negative value from Bing. Unfortunately, we don't have details from the previous testing because Live Search failed to crawl and index all of the pages for the first test.
Outcomes

The first thing to consider is users, as it always should be. 508 Compliance is an extremely important thing to understand and adhere to, for more information go to Section 508. Basically, use of alt elements and accurately describing the image is the right thing to do.

Second, based upon the results of both tests combined, the alt element has the most weight in all engines. Using the alt element only will give you top rankings for non-linked images in Google and Bing and second in Yahoo. For linked images, it ranks second in Google and Yahoo.

If you are trying to get the most from your images, linked or not, here is the order of value:
ALT only - Average Position 1.60
None - Average Position 2.4
Both - Average Position 3.00 tie
Title only - Average Position 3.00 tie

If you are trying to get the most from your non-linked images, here is the order of value:
Alt only - Average Position - 1.33
None - Average Position - 1.67
Both - Average Position - 3.33
Title Only - Average Position - 3.67

If you are trying to get the most from your linked images, here is the order of value:
Alt only - Average Position - 2.00 tie
Title only - Average Position - 2.00 tie
Both - Average Position - 2.50
None - Average Position - 3.5

My thought is to include the alt element and forget about trying to add more value by using the title element, it looks like it is more effort than it is worth (which is little).

What are your thoughts?

About the Author:
In-house SEO for a private travel company with great success. Has been influential in developing and building a niche travel directory and search engine. I enjoy learning and sharing information on my blog, SEOPittfall.com to others in an effort to build relevant, content driven websites with the user in mind.